150-watt load tester USB voltage display wrong - how to fix?

After looking at Dodge Reviews youtube video, I saw the 150-watt load tester, and ordered one (it was less expensive in the ATorch AliExpress store than in BG, so I got it from there).

Upon receiving the unit, I immediately tested it (I was planning to use this for testing batteries at higher currents (the EBD-USB+ can only test up to about 3-4 amps and would require USB to alligator clip which introduces resistance, plus the USB cable would likely not be able to transport higher current, eg. 10 amps at nominal lithium-ion voltage 3.7v)

On testing, I initially only tested USB devices, and using the USB A, micro-USB, USB-type C ports, the voltage readings are always too high (real 5.0v will display "8.0v"; real 3.9v will display "6.1v")

Only later when I tried using the wire-terminal, did I notice it displays correct voltage (within some tolerance).

Initially I though of calibrating the unit (which seems to require an accurate 30v power supply, but I don't have one, so I just did a factory reset of the load tester. Which resulted in the same wrong displays (when using any of the USB outputs). What do you think could be at fault and can it be fixed somehow?

I’ve gotten in touch with ATorch where I obtained this 150-watt load tester.

They analyzed the photos and video I sent them, and they asked me to try to short-circuit the 2 wire-terminals.

Lo and behold, when I short the 2 wire terminals, the voltage screen display will now be correct (well, within some tolerance).

But that seems to be a temporary fix. I wonder if other people also need this “fix” for their USB voltages to show correctly? And also if there is a more permanent fix?

Update:

ATorch replied to me and mentioned that the fix is to change the diode… posting it here in case someone else has encountered this issue, will find this as a reference.

(I still haven’t changed mine… waiting for them to send the replacement part)

What purpose do you recommend this 150W load tester for?

For which purpose do you use the 150W load tester?

I originally planned to use this to test how some power adapters to check how much voltage drop they would incur when loaded.

For instance, I tested the 60watt (rated “12v 5A”) power adapter that comes with the MC3000 and another one from the Miboxer C4-12.
I plugged the DC12v 5.5/2.1mm plug to this 150-watt tester, now I increase the amps to about 5amps. And the voltage are holding well — I recall the voltage still stayed at least 11.5v or higher even when I loaded 5+ amps on both of those power adapters.

I also tested the power adapters of a few others (eg. the one bundled with Lii-500 Engineer), which also held up well when I loaded the amps to its rated amps.

However, I also tried buying a supposedly 60-watt DC12v5A power adapter from Banggood, which was just around $7-8. Now I understand cheap power adapters usually don’t hold up to their true rating, but it was much lower than I expected — when I plug to the above load tester, set the load at 3 amperes or less, the voltage has already dropped below 10v! I think it can only hold up to around 2.5 Amps and stay at the 11.5v mark.
I had initially wanted to do a video review to the BG product link and use the above setup to show that their claimed 60w 12v5A power adapter is only about 2.5amps actual, but didn’t get around to making a video of it…

But now I know this cheap “12v5A” doesn’t really perform as intended and is quite bad (I had bought that 12v5A but intend to use at max 3 amps, but it looks like it couldn’t even hold 3 amps without the voltage sagging a LOT!)

~

Another intended use was to check how much voltage drop if I applied say 5 amps or 8 amps or 10 amps to an 18650 battery. However, I think I need a very good battery holder if I want to measure the voltage sag properly. (This is to test which batteries will have lower voltage sag when loaded). I currently only have some cheaper battery holder, with not-so-thick wires, so I don’t think they will hold 8 amps or 10 amps without the wires getting hot though and giving much lower voltage reading.)

I already have the EDD-USB+ but it can load up to around 4 amps max only.

Don’t know about d_t_a but I’d like to get one to test batteries between 10A-20A load to see if I’m getting fakes.

Yep. This is the main reason I also bought a constant current electronic load.

It allows to check the internal resistance off a real checked cell against others.

Hi d_t_a.
I have the same USB voltage error with my 150w load.
Bought the diodes to try to correct the problem.
Thanks for the information.
As soon as I receive the diodes I will post here the results.

mozart.f

ATorch, the store where I got it from, had been quite helpful, and they sent me a replacement board when I mentioned I’m not sure where to source the diodes from…

I transplanted the CPU fan, stand-offs from the old board to the new replacement board they sent me, and the new board seems to work properly now.

Also, before I got the replacement board, ATorch also adviced me to try something first: short the 2 wire terminals, which temporarily fixes the problem (when using the USB ports) — I mentioned in Post #2 above.

Hi d-t-a.
I received the diodes today and replaced then.
As expected, now voltage readings on the USB ports are correct.
This fix works!
Thanks for the great help.

Glad to help.

Hopefully other people who also encountered this issue can find this message thread and try to fix it first themselves if they’re skilled enough to do so.